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Flashcards in Sea Level Changes Deck (40)
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1
Q

Sea level changes are…

A

Eustatic or isostatic

2
Q

Eustatic sea level change

A

A global change in sea level resulting from a fall or rise in the level of the sea itself (volume of water in the sea changes/change in the shape of the ocean basins)

3
Q

Eustatic change causes (2 points)

A
  1. Changes in climate
    - increase in temp = ice sheets melt, water expands (increased sea level)
    - decrease in temp = more snow, more water stored in glaciers so volume of sea is reduced (sea level decreases)
  2. Tectonic movement
    - shape of ocean basins are altered and thus volume also
4
Q

Eustatic change always has g______ effects

A

GLOBAL

5
Q

Downward movement of the land causes…

A

Sea level to rise locally

6
Q

Uplift of land causes…

A

Sea level to fall

7
Q

Isostatic sea level change

A

Local changes in sea level resulting from the land rising and falling relative to the sea

8
Q

Even today, ___ years after the last ___ _____ ended the UK is still readjusting to not having its ___ load

A

10 million
Ice age
Icy

9
Q

UK Isostatic Change Situation

A

The north of the UK is rising, e.g Ben Nevis at 2mm per year

The south of the UK is sinking, e.g Brighton at -0.4mm per year

10
Q

The main causes of isostatic sea level change are… (3 points)

A
  1. Uplift/depression of Earth’s crust
    - Melting ice sheets = uplift as no more weight on land (rebound)
    - Accumulation of sediment = depression
  2. Subsidence of land
    - caused by shrinkage of land after abstraction of groundwater
  3. Tectonic processes
11
Q

Tectonic movement leads to an _______ in surface area of land. This means that the water is more ____________ into a ___________ area and so ocean depths increase.

A

Increase
Condensed
Smaller

12
Q

Tectonic Process Explanation

A
  1. Global temps cool, ice forms as glaciers and ice sheets
  2. These ice forms reduce water in oceans (eustatic fall)
  3. The relative fall in sea level is moderated by the ice that forces land to move down (Isostatic change)
  4. Climate warms ice melts sea level rise
  5. Flooding occurs, submergent features form
  6. Once ice is removed Isostatic rebound can occur - slow
  7. Prolonged rebound - allows emergent features such as raised beaches which sit above sea level
13
Q

Isostatic changes + eustatic changes =

A

FLOODING

Land sinking and sea level rising

14
Q

Sea level has _____ in the last _________ years

A

Risen

10,000

15
Q

Sea level varies on a _____ basis with the tidal cycle.

Onshore winds and ______ atmospheric pressure systems also called the sea surface to _____ temporarily.

A

Daily
Low
Rise

16
Q

Draw time line of global sea level

A

Refer to textbook

17
Q

Climate change causes changes in

A

Sea level

18
Q

Change in average temperature between 1900 and 2016

A

1.08 C

19
Q

Causes of climate change and HOW they cause it

A

Human activities (deforestation and burning fossil fuels)

Increase conc of greenhouse gases, these absorb outgoing long-wave radiation, so less is lost to space

As more energy is trapped the plant warms up

20
Q

Impacts of climate change

A

Increase in sea level through melting ice sheets and thermal expansion of water in oceans

21
Q

Global sea level is currently rising at _mm per year

A

2

22
Q

Impacts of climate change on coastal areas…

A
  • More frequent and severe coastal flooding
  • Submergence of low-lying islands
  • Changes in the coastline, e.g island formation
  • Contamination of water sources and farm land (salt)
  • More coastal erosion and stronger storms
23
Q

SEA LEVEL FALL results in

A

Coastlines of emergence

24
Q

Landforms of emergence (3)

A

Raised beaches
Relict/fossil cliffs
Marine terraces

25
Q

Raised Beaches

Formation?
Example?

A

Formed by wave action
Fall in sea level/rise in land puts beach beyond the waters reach at the high tide mark

West Coast of Scotland

26
Q

Marine terraces

Formation?
Example?

A

Sea level falls
Wave cut platforms exposed
Land uplifted
Platforms preserved as terraces above the ocean

Croatia

27
Q

Relict/fossil cliffs

Formation?
Example?

A

The cliffs are no longer exposed by the sea and slowly get covered by vegetation
These raised features are gradually weathered over time

28
Q

SEA LEVEL RISE results in

A

Coastlines of submergence

29
Q

Landforms of submergence

A

Rise
Fjords
Dalmatian coastlines

30
Q

Rias

Formation?
Example?

A

Water enters a valley and partially submerges it

Rias have a gentle long and cross profile
Wide and deep at mouth
Narrower and shallower inland

Milford Haven, South Wales

31
Q

Fjords

Formation?
Example?

A

Movement of a glacier that cuts rock formations
Steep ridges formed on each side of glacial valley
Valley fills with water

Western Norway

32
Q

Dalmatian coastlines

Formation?
Example?

A

Valley lies parallel to coast
Increase in sea level
Valley flooded
Islands left parallel to the coastline

Named after the Dalmatian coast in Croatia

33
Q

The sea level changes due to 2 factors

A

Subsistence of the coastline

Increase in water volume of the ocean

34
Q

Subsistence

A

Coastal areas sinking - often this is due to access groundwater extraction. Has the effect of making the sea level higher

35
Q

Water volume

A

Changes due to either thermal expansion or addition of extra water from land stores (ice melt)

36
Q

Processes _____ and _____ landforms over time

A

Create

Alter

37
Q

Individual ________ combine to form _________. Coastal landscapes can be dominated by ________ or _________ but both are formed by both

A

Landforms
Landscapes
Erosion
Deposition

38
Q

A change in one factor leads to changes in others.

Example?

A

Change in wind direction could increase deposition and change a landscape dominated by erosional landforms to one dominated by depositional landforms

39
Q

Changes can occur over a range of _____ scales and ______ scales

A

Spatial
Temporal

E.g storm - hours
Tectonic uplift - thousands of years

43
Q

The Maldives: Sea Level Rise

A

3mm per year
Airport - 1.2m above sea level, only point of access
1.2 million tourists per year
1/3 of GDP tourism